1. Field of the Invention
The present invention relates to a control apparatus for a composite appliance for efficiently controlling an image input apparatus such as a scanner and an image output apparatus such as a printer.
2. Description of the Related Art
There has conventionally been put to practical use an image processing apparatus called a digital composite appliance such as a copying machine or facsimile which is equipped with a combination of an image input apparatus such as a scanner and an image output apparatus such as a printer, or a computer system which is equipped with an image input apparatus and image output apparatus as separate component units. To realize composite functions such as an image input function, image output function, and copying function in this image processing apparatus, when the image input apparatus and image output apparatus cannot operate in synchronization with each other, the copying function is realized by outputting, to the image output apparatus, image data temporarily stored from the image input apparatus in a memory. When the image input apparatus and image output apparatus can operate in synchronization with each other, the copying function is realized by disposing a passage for directly transferring an image signal from the image input apparatus to the image output apparatus.
To connect the digital composite appliance to a control apparatus such as a computer and effectively use the appliance as an input/output device for the computer, the appliance is not simply connected to a low-speed signal line such as a computer I/O, but must perform fine control and be connected to the computer itself through a high-speed bus. In this manner, the composite applicant is demanded not only to function as a subordinate side when viewed from the control apparatus but also to be used as an independent device.
The present invention has been made in consideration of the above situation, and has as its object to provide a control apparatus for a composite appliance capable of functioning as the subordinate side of the control apparatus and functioning as an independent device.
To achieve the above object, the control apparatus for the composite appliance according to the present invention reads the value of an external switch, and checks whether the apparatus serves as a control side or subordinate side. If the control apparatus serves as a subordinate side, it waits until the control side writes a configuration through a bus. If the control apparatus serves as a control side, it sets necessary values in itself, and writes a configuration in a device on the bus. In this way, the control apparatus can operate as both the control side and subordinate side.
The present invention comprises the following arrangement. That is, a control apparatus for a composite appliance, comprises evaluation means for reading and evaluating an externally set value, an input/output bus, and switching means for switching in accordance with a result of the evaluation means whether the control apparatus operates as a control apparatus using a device connected to the input/output bus or as a subordinate-side apparatus used by the device.
It is preferable that when the control apparatus be switched to a control side in accordance with the result of the evaluation means, the switching means execute an operation for recognizing a configuration of the device connected to the input/output bus.
It is preferable that the switching means write a predetermined value in a predetermined register when the control apparatus is switched to a control side in accordance with the result of the evaluation means, and allow the register to write a value from a device on the input/output bus when the control apparatus is switched to a subordinate side.
The switching means preferably writes the predetermined value in the register through the input/output bus in writing the predetermined value in the register when the control apparatus is switched to the control side in accordance with the result of the evaluation means.